Data structures and algorithms crash course with animated illustrations and off-the-shelf code

Dive in GitHub

500 animated illustrations, 14 programming languages, and 3000 community Q&As to help you quickly get started with data structures and algorithms


“An easy-to-understand book on data structures and algorithms, which guides readers to learn by minds-on and hands-on. Strongly recommended for algorithm beginners!”

—— Junhui Deng, Professor, Department of computer science and technology, Tsinghua University

“If I had 'Hello Algo' when I was learning data structures and algorithms, it would have been 10 times easier!”

—— Mu Li, Senior principal scientist, Amazon

Animated illustrations

It's crafted for ease of understanding, ensuring a smooth learning journey.

"A picture is worth a thousand words."

Animation example
Running code example

Off-the-shelf code

Featuring multiple programming languages, all runnable with a single click.

"Talk is cheap. Show me the code."

Learning together

Welcome discussions and questions with open arms.

"Learning by teaching."

Comments example


Code reviewers


This book has been enhanced through the collaborative efforts of more than 100 contributors. Thanks for their invaluable time and input!